An apparatus, method and article for maximizing solar charge current through the use of split wire(s) in a solar array with solar panels connected in the combination of series and parallel

ABSTRACT

In a maximum power point tracking (MPPT) solar charging system, the solar array is re-configured to have the majority panels connected in parallel, while some panels remain in series for MPPT charge controller. The split wire(s) from the string of panels connected in series can be connected to all the other panels connected in parallel. The split wire is connected to the apparatus_Solar Charge Maximizing controller, to directly power a direct current_DC load, and to charge a battery or battery bank with the same nominal voltage. The solar charge maximizing controller(s) works in conjunction with MPPT charge controller(s) to maximize the total charge current in the ever-changing solar radiation conditions and in the constant changing DC load (inverters in general) conditions.

The previous arts are cited below.

-   PHOTOVOLTAIC POWER REGULATION SYSTEM_CA 1226895, CPC 320/11, IPC    H02J 7/00(2006 January), H02J 7/35(2006 January), 1987-09-15 by    Jaster, Dale R.-   SOLAR POWERED DC LOAD SYSTEM_CA 02762531, IPC H02J 7/00(2006.1),    H01L 25/00(2006 January), 2012-01-06, by Carroll, Min-   SOLAR POWER MANAGEMENT SYSTEM_U.S. Pat. No. 8,258,741 B2, Sep. 4,    2012, by Wu et al.-   PHOTOVOLTAIC POWER STATION_U.S. Pat. No. 10,381,840 B2, Aug. 13,    2019, BY Shuy et al.-   ADAPTABLE RECHARGING AND LIGHTING STATION AND METHOD OF USING THE    SAME, U.S. Pat. No. 10,014,683, Jul. 3, 2018, by Ellenberger et al.-   SOLAR POWER STORAGE MODULE AND SYSTEM AND SOLAR POWER SUPPLY SYSTEM,    U.S. Pat. No. 9,082,897 B2, Jul. 14, 2015, by Liu et al.-   SOLAR PANEL INTERCONNECTION SYSTEM, United States Patent Application    20190019908, Jan. 17, 2019, Kind Code A1, LEKX, David John, et al,    Jan. 17, 2019.

The reference is cited below.

-   A MICRO POWER MANAGEMENT SYSTEM AND MAXIMUM OUTPUT POWER CONTROL FOR    SOLAR ENERGY HARVEST APPLICATION_IEEE ISLPED, pp. 298-303, August    2007, ACM New York, USA, by Shao et al.

FIELD OF THIS INVENTION

The present invention relates to a solar power supply system with arechargeable solar energy storage battery or a battery bank with batterymanagement system (BMS) or without BMS, for the power supply to anoff-grid solar system with an off-grid inverter, or a hybrid off-gridsystem with automatic transfer switch. The efficiency of a solar arrayis maximized by connecting the split wire (PVs) from a solar array to asolar charge maximizer to power the DC load directly and to charge abattery or a battery bank at the same time. The present invention canalso be used in a grid-tie systems and even solar power plants at alldifferent capacity levels.

BACKGROUND ARTS

As a conventional art, the maximum power point tracking (MPPT) solarcharge controller is far more efficient than the Pulse Width Modulated(PWM) solar charge controller. Both MPPT and PWM charge controllers aredesigned for charging conventional flooded or sealed lead-acid, GEL,absorbent glass mat (AGM) solar storage batteries. They have both beendesigned mainly for the controlled charging to extend the batteryservice life, and to minimize gassing from those batteries, but not tomaximize the charging current according to the available energy from asolar array. Some of the MPPT solar charge controllers may also be usedto charge a lithium-ion battery, but they all have limited chargingcurrent capacity.

In term of load carrying capacity, both MPPT and PWM charge controllersare generally not designed to allow the battery (or battery bank)charging while the large load is connected to the system. The highdirect current (DC) draw from the system may cause the charge controllerto limit the charging current to “protect” the battery, and end upwasting the available solar energy as a result. The ever-changing(fluctuating) current draw, sometime can be as high as 100 or 200 ampsor even 400 amps current draw or as low as a few amps, is very common inan off-grid or a hybrid solar energy system. However, a conventionalMPPT or PWM solar charge controller may allow a direct DC loadconnection of maximum 5 amps or 10 amps or 20 amps only.

Both MPPT and PWM solar charge controllers' capacity are limited to haveabout maximum 100 amps charging current. Higher charging current cancause significant over-heating of the MOSFET or JFET or CMOS or othertransistors inside the MPPT or PWM solar charge controllers. Majority ofthe solar charge controllers will have to run interior cooling fan(s) tolow the components' temperature to prevent its components fromoverheating whenever the charging current reaches 20 amps and over, evenfor the controllers that consist of large chunk of aluminum heat sink.The cooling process results in wasting energy and making a lot of fannoise. Some of 60 amps solar charge controllers will have its coolingfan kicks in at 1 amps charging current for extending the service lifeof the charge controller. Others would just lower the charging currentfor self protection, despite the maximum solar conditions available.

In a multiple MPPT charge controllers system, the total chargingamperage may be increased. However, it is almost impossible for all theMPPT controllers to work at maximum power point at the same time. As oneof the MPPT controllers scan through different operating points to findthe maximum power point in a nice sunny day with maximum solar radiationconditions, other charge controllers will loss the tracking of themaximum solar conditions.

Furthermore, A MPPT charge controller works better during a cloudy daywith minimum and consistent solar radiation conditions, when the maximumpower point can be easily tracked. And it does offer some advantage foraccepting higher voltage input to save the wiring cost for a solararray. But as soon as the sun is shining, the amount of solar radiationreaching the earth's surface varies greatly because of changingatmospheric conditions and the position of the sun, both during the dayand throughout the year. The partial shading on a single solar panelwill have significant impact on the whole string that is connected inseries.

The traditional MPPT solar charge system has the solar panels connectedin series, and it may also include many parallel strings with samenominal voltage of panels in series. A typical residential or lightcommercial off-grid MPPT solar charging system may include 10-30 panelswith about 300 watts capacity each, for a total of 3000 watts to 9000watts, or even more capacity. It is nearly impossible for a MPPT chargecontroller system to ensure each every solar panel operating at maximumpower points, especially in the high solar radiation conditions.

The previous art, PHOTOVOLTAIC POWER REGULATION SYSTEM_CA 1226895, CPC320/11, IPC H02J 7/00(2006 January), H02J 7/35(2006 January), 1987 Sep.15 by Jaster, Dale R, relates to an apparatus for controlling the chargerate and voltage of storage batteries of a solar power generating systemusing a single voltage regulator module to monitor and control the stateof charge of any number of cells of a battery and a number of solarmodules. It related to the charge control, but not to maximizing thecharge current from a solar array.

The previous art, SOLAR POWERED DC LOAD SYSTEM_CA 02762531, IPC H02J7/00(2006 January), H01L 25/00(2006 January), 2012 Jan. 6, by Carroll,Min, does relate to solar panel with battery and DC load. But the DCload is limited to powering a water pump and an illumination system. Italso involves in the load control to turn on/off the LED lightsautomatically during the day.

The previous art, PHOTOVOLTAIC POWER STATION_U.S. Pat. No. 10,381,840B2, Aug. 13, 2019, BY Shuy et al. teaches us that a solar power stationpower supply is maximized by providing an energy reservoir in a grid-tiesystem to supply power to the grid. This art teaches us about the“Maximum Energy Utilization Point tracker” (MEUPT) Optimizer to capturethe out of phase surplus energy through the use of an energy reservoir,and use the captured energy to provide power in a grid-tie systemthrough synchronization with power grid in a power station with acapacity in the Mega Watt (MW) level. This art does not relate to anoff-grid system with an off-grid inverter in the Kilo Watt (KW) range.

In another previous reference publication, A MICRO POWER MANAGEMENTSYSTEM AND MAXIMUM OUTPUT POWER CONTROL FOR SOLAR ENERGY HARVESTAPPLICATION_IEEE ISLPED, pp. 298-303, August 2007, ACM New York, USA, byShao et al., teaches us the light energy harvesting applications throughan inductor-less on-chip micro power management system. The systemtargets at wide variety of applications that operate at differentlighting environments ranging from strong sunlight to dim indoorlighting where the output voltage from the photovoltaic cells is low.The system has a step-up charge pump that is used to directly operatethe circuit or to charge a rechargeable battery. Low power circuitdesign is proposed for the implementation of the system maximum outputpower control through the implementation of a 0.35-mum CMOS process.This reference does address the “charge pump” used for direct operate aDC circuit. But it generally limited to limited current control in thesolar cell level. The amperage range is nowhere near the solar panelslevel with a few hundred amps in an off-grid solar power supply system.

In the other previous art, SOLAR POWER MANAGEMENT SYSTEM_U.S. Pat. No.8,258,741 B2, Sep. 4, 2012, by Wu et al, teaches us that a solar powermanagement system is provided for managing electric energy conversion bya photovoltaic cell module, supplying the converted electric energy toan external load, and storing the converted electric energy in abattery. The solar power management system comprises a multiphasemaximum power tracking (MPT) module, a charging circuit and a voltageconversion module. The multiphase MPT module regulates output current ofthe photovoltaic cell module to output maximum power within the highlimit thereof and obtain improved solar energy conversion efficiency.The voltage conversion module converts the electric energy generated bythe photovoltaic cell module into different voltage formats, such as5.6V DC, 1.0V DC, 0.6.about.0.3V DC low voltage, or −1.2V DC negativevoltage, to meet different external load requirements. The solar powermanagement system has simple circuitry and can be configured as a systemon chip (SoC) at reduced cost while provides very wide applications. Theapplication of this art is also limited to micro power supply system. Itrelates to solar cells level with low DC voltage and current. It doesnot relate to the solar panel level in the application of an off-grid oran off-grid hybrid system.

There is another art, ADAPTABLE RECHARGING AND LIGHTING STATION ANDMETHOD OF USING THE SAME, U.S. Pat. No. 10,014,683, by Ellenberger etal, Jul. 3, 2018. It does relate to a self-contained rechargeable powersystem, whether there is a power grid or no grid at all. But it ismainly related to different type of batteries with solar array to powerlight emitters and/or exterior electronic devices through charge port.It relates to a customizable system that may include one or more lampsand one or more charging ports for external electronic devices thatutilize solar and/or battery power. The system also has limited powercapacity. And it does not address the maximum power capacity requiredfor a complete off-grid system, in case of cottage or remote areawithout a power grid at all.

The art, SOLAR PANEL INTERCONNECTION SYSTEM, United States PatentApplication 20190019908 Kind Code A1 LEKX, David John, et al, Jan. 17,2019. It relates to a back sheet for a solar panel assembly.

There is also art, SOLAR POWER STORAGE MODULE AND SYSTEM AND SOLAR POWERSUPPLY SYSTEM, U.S. Pat. No. 9,082,897 B2, by Liu et al, Jul. 14, 2015.The system does have a capacity to maximize the power supply capacity.But it does not relate to an off-grid system with a battery or a batterybank.

There are numerals arts and products have been developed in recent yearsfor a grid-tie system to have the solar energy generated by large scalesolar array directly sent to the grid through a grid-tie inverter ormany micro-inverters. The system may also include a large capacitylithium-ion based solar energy storage battery or battery bank to storeenergy in case that the grid is down. It may also include sophisticated,web-based power management system for remote control. A typical suchsystem is the TESLA POWERWALL systems with 13.5 KWH lithium-ion batteryand an integrated grid-tie inverter. The 13.5 KWH POWERWALL system willsupport 5 KW continuous power draw from the lithium-ion battery withliquid thermal control. However, the lithium-ion battery in thePOWERWALL system is charged by the AC power. When the grid is down formore than a few days, the system will also be down, because the batteryis not designed to be directly charged by the solar array in this typeof the systems.

As the matter of fact, the application for a grid-tie system withso-called “net metering” program to the local utility company is not aneasy task. There are many stakeholders involved, such as energyretailer, consumer, generator, distributor, service contractor,installation contractor, inspectors, local utility company, localgovernment, etc. . . . . The law and regulations are also ever-changing.The application process is a daunting task for a regular home or smallbusiness owner. For a micro-generation facilities 10 KW and under inCanada, the inverter-based unit must still follow the rule of “no morethan 0.5% DC injection to the grid” and “harmonic levels must bemaintained below CAN/CSA-C61000-3-6 standard”. There are lots of morerules to follow in the grid-tie system. Such scale of Micro FIT grid-tiesystem is generally not feasible, despite the fact that solar panelprice has dropped significantly over the years.

In the meantime, the price for lithium-ion battery has also droppeddramatically. The present invention has just come in the right timing toopen up the huge market at the independent home and small buildinglevel. The off-grid or hybrid solar system serving residential homes orsmall buildings can cut the owners utility bills by 30% to 100%. Thelevel of reduction depends on the total electricity consumption, daytimeelectricity consumption, and total capacity of the battery bank and thenumber of solar panels installed. There is no critical requirement foran off-grid inverter, even a modified sine wave inverter may be used topower non-critical & non-inductor load, such as stove for cooking. Incase of a hybrid off-grid system, a pure sine wave inverter may even beused to power the personal computers. And an 5.0 KW automatic transferswitch (ATS) may switch the power source between utility grid and theinverter in 10 to 16 ms (mini-seconds) without interrupting or resettingthe operating personal computer(s) with no UPS_uninterruptible powersupply attached to it. A solar charge maximizer in the present inventioncan boost the 100 amps capacity limit of a MPPT system up to a maximum300 amps with minimum extra cost. A solar charge maximizer system with300 amps capacity in a 24 v nominal voltage system can support up to 7.2KW of total capacity from solar panels.

SUMMARY OF THIS INVENTION

Present technical problems are listed below.

1. The implementation of a traditional grid-tie solar system with a fewkilowatts up to 20 kilowatts capacity, at individual homes or smallbuildings with limited available roof area or small land, is generallynot feasible due to complicated application process, and ever-changingrules and regulations. There are too many obstacles in the net meteringprogram across the world, despite the advantage of cost saving for asolar system without energy storage battery or a battery bank. There arealso many restricted technical requirement for a grid-tie inverter and anet meter. The home or business owner must become an energy generator,as soon as the grid-tie system is connected. This is a daunting task fora regular home or small business owner. There have been numerals reportsabout the application process delay. Some home owners have spent over$60,000.00 dollars to have the solar panels installed, but just sitidling for the grid-tie approval. Others may have the grid-tie built,but the distributor could appeal to the court to have price reduced forany power coming out from the meter to the grid anytime in the future.On the other hand, the energy distributor must ensure the pure sign wavepower source in the whole power grid. Too many small generators in thegrid will for sure cause the harmonic levels issues, or higher DCcontent in the grid, and further compromise the power quality for allother customers in the same grid.

2. There are some grid-tie systems with solar energy storage capacity.But there is no exception for such system in the grid-tie applicationapproval process. Furthermore, such system still needs the AC power fromthe grid to charge the battery. When grid is down, the system will alsobe down after the energy in the battery will be depleted.

3. The traditional on/off solar battery charging method has been takenover by PWM and MPPT solar charge controllers. The MPPT solar chargecontrollers do offer some advantages for accepting higher and flexiblesolar power input voltage. The MPPT solar charge controller will alsowork well at steady solar radiation conditions. The MPPT solar chargecontroller will also adapt to different battery voltage. However, theMPPT solar has been designed to charge and protect GEL battery, sealedand flooded lead acid battery and AGM battery. The high current drawfrom an off-grid or a hybrid system wills generally cause these types ofcharge controllers to limit the current output to “protect” the battery,and end up wasting the available solar energy from a solar array.

4. The traditional lead acid, GEL, AGM solar energy storage batteries,in the off-grid systems, have been gradually replaced by lithium-ionbased batteries, such as lithium-ion phosphate (LiFePo4) batteries.Lithium-ion based battery does not need the same protection as traditionbatteries. The lithium-ion based batteries always have its own batterymanagement system (BMS), it is always preferred to have maximum chargingcurrent as long as the charge current is below the maximum chargecurrent allowed for the lithium-ion battery or battery bank. Some of theMPPT solar charge controllers do allow the users to set it up forlithium-ion battery charging, but the charge current is generallylimited to 100 amps maximum. A 100 amps MPPT solar charge controller mayactually only 55 handle maximum 50 amps of continuous charging current.The overheating of electrical components in the MPPT solar chargecontrollers may be controlled by adding large heat sink or integrating acooling fan in the system. But the charging current capacity is alwaysbelow the minimum required for an off-grid solar power system of anormal residential home. Furthermore, the MPPT solar charge controllerwill have to waste significant amount of energy to scan through a set ofdifferent operating 60 points to find the maximum operating points,especially when the solar radiation changes rapidly at maximum solarconditions. A high current capacity MPPT solar charge controller is alsovery expensive.

5. It is preferred to have the panels connected in series for maximumvoltage input in a MPPT solar controller system to save the wiring cost,but shading on any single panel in a string with its panels connected inseries will always have significant impact on the output of the wholestring of the solar panels. While solar radiation conditions in a solararray located in the urban area is ever-changing due to the shading fromtree and building structure, or solar panel orientation. The birdsflying over a solar array can cause the energy output of a MPPT solarcharge controller system to drop dramatically.

6. There are similar situations in the string inverter in grid-tiesystems without any battery storage. The string grid-tie inverters comewith MPPT technologies built in the inverters to accept over 1000V oreven 1500V voltage from the string with all panels connected in series.These kinds of inverters are generally not efficient in response to therapid varying solar condition changes, especially when there is partialcloud covering certain number of the solar panels.

7. There are also micro-inverters, or power optimizers systems used forlarge scale of grid-tie solar generator applications in recent years.They are more efficient than string inverters, but they are not trackingthe maximum solar condition so well. The inverters in micro scale aremore likely to inject more DC content to the grid. Most importantly,there are a lots of small sensitive electronic devices located next tothe solar panels without any climate control. Maintenance cost is high.And there are numerals reports about catching fires of these types ofdevices on the roof recently. When think about so many small devices allover the place on the roof, one shall have no problem to understand whythere is so much risk.

Solution to the Problems

In a solar charge maximizer system according to present invention, theoptimum battery charging operating point is actually maintained by thebattery or battery bank with the same nominal voltage of the solarpanel's nominal voltage. The split wire from a string with solar panelsconnected in series can be used to charge the battery or battery bankand to power the DC load (inverter) directly. An automatic transferswitch in a hybrid off-grid system or a hybrid grid-tie inverter canalways be set at a range, so that the battery voltage matches theoptimum operating voltage of the split wire voltage from a solar array.

In a solar charge maximizer system, a MPPT solar charge maximizer canstill be installed to charge the same battery or battery bank at thesame time in the same system. The benefit of a MPPT solar chargecontroller is not compromised, while the mechanical contact switch inthe solar charge maximizer can increase the charging current capacitysignificantly without any other system components overheating. Thestaged contact switch design will ensure much higher charging currentavailable at maximum solar radiation conditions, and yet consume minimumpower for the solar charge maximizer to charge the battery at minimumsolar radiation conditions.

A solar charge maximizer system with an automatic transfer switch and anoff-grid inverter can be implemented for individual homes and smallbusiness with limited available roof or land area for solar panels,without grid-tie system approval from a local utility company or anenergy distributor. The system would only generate enough electricalenergy for the owner's own use, without affecting any other customers inthe grid. The solar charge maximizer system owner may ensure theself-sufficient power supply by increasing the battery storage capacity,and install the maximum number of the solar panels that are possiblyallowed in their own facilities. The hybrid system design with automatictransfer switch will ensure the power supply within the home or facilityeven when there is no solar energy available for a long period of thetime. With many small solar maximizer systems behind the meters in theindividual homes and small buildings in the whole region, the maximumdemand for the local power grid will drop dramatically. As a result, thesame grid will support more customers without upgrading the existinggrid infrastructure. And most importantly, the hybrid off-grid systemswill not compromise the power quality of the grid. A solar chargemaximizer can still work in the hybrid grid-tie system. The battery inthe system will serve as a buffer storage battery. And the batterycapacity can be reduced by feeding excessive power to the grid through ahybrid grid-tie inverter, when excessive energy could not be used withinthe facility. However, such hybrid grid-tie system will still needgrid-tie approval from the energy distributor or utility company.

The solar charge maximizer system is especially very useful for thehomes, businesses and buildings with high daytime electrical powerconsumptions. In such systems, the more daytime electrical consumption,the less capacity of the battery or battery bank will be required, andthe more significant reduction to the local electrical grid power demandcan be achieved. A solar charge maximizer system with battery, inverterand automatic transfer switch can be customized to serve specificcircuit(s) with higher daytime load demand. It can also be customized toserve dedicated circuits with critical load in those circuits. Thesystem is very flexible, there is no need to have the whole house orwhole building go off-grid. Most importantly, the present invention canreduce the power demand from a local grid significantly during the peakhours when the present invention will be applied to the majoritycustomers in the grid. And the existing grid infrastructure can supportmore customers and urban development without the need for major upgradeto the grid infrastructure.

The numeral testing results by comparison between a MPPT solar chargecontroller and a solar charge maximizer have proved that a solar chargemaximizer will outperformed many MPPT solar charge controllers, based onthe system with the same solar panels. The effective charging currenthas been compared. The MPPT solar charge controllers from many famousmanufactures with all range of current capacities have been tested. Theyare compared in all solar radiation conditions, from charging at highsolar radiation condition to moon-light charging. Surprisingly, a solarcharge maximizer would outperform many of the MPPT charge controllerseven in the moon-light charging conditions, and during a cloudy day. Thetesting has been conducted by clamping the charging current to the samelithium-ion phosphate (LiFePo4) battery bank.

It is the contractor, installation technician or system designer'sresponsibility to ensure that the split wire has the same nominalvoltage as the battery or battery bank's nominal voltage in the system.Take the 24V lithium-ion phosphate (LiFePo4) battery system as anexample, the 60 cells solar panel would have an optimum operatingvoltage of 31.0V (Vmp=31.0V) at standard test condition (STC 25 C).While a 24V automatic transfer switch (ATS) serving the 24V lithium-ionphosphate battery can be set to use the grid power when battery voltagefall down below 25.0V, and use the battery power when the batteryvoltage reach 28.0V. This would be perfect range for a 24V lithium-ionphosphate battery or battery bank. At this setting range for the ATS,the relay in the ATS is not likely to enter into a short cycling(constantly on/off) state, as long as the battery capacity is sizedproperly, since 24V lithium-ion battery would normally have a fullycharged voltage of 26.8V. At 28.0V charging voltage, the LiFePo4 batterywould already have sufficient capacity to prevent the voltage fallingbelow 26V should the ATS kicks in to use the battery power. The cellnumber may be increased to 72 cells in the hot climate regions or zones.The “Vmp” may fall below 28.0V for a 60 cell panel when its temperaturereaches 60 C degree. The 24V lithium-ion battery would normally accept acharging voltage of maximum 29.2 voltage, and cut off the power supplywhen the voltage falls below 20.0 or 22.0 v. In 24V nominal voltagesystem, an off-grid inverter has an operating voltage range between22.0V and 30.0V. The inverter will generally set off alarm when thevoltage falls below 23.0V. A solar charge maximizer shall normally beset at 26.8 to start charging a lithium-ion battery or battery bank, andto stop charging when the voltage reaches 28.8V. This would be theappropriate range to maximize the solar energy harvesting automatically.However, the field technician, or system designer must ensure that thebattery bank maximum charging current is sufficient to accept themaximum current from a solar array. If the battery bank charging currentcapacity was too lower, the charging voltage would be constantlyreaching over 29.0 v to cause the solar charge maximizer to stopcharging, or the BMS in the lithium-ion battery will prevent thecharging to protect the battery. The result would be wasting theavailable solar energy. All the voltage number listed above is for thenominal 24V lithium-ion battery and battery bank with BMS. The voltageand cell number shall be reduced to half if it is a nominal 12V solarsystem, doubled if it is a nominal 48 v solar system.

In case of other types of energy storage battery, such as lead acid,GEL, or AGM battery, the “stop” charge voltage value in the solar chargemaximizer must be set at a voltage below the floating charge voltage bythe field technician. The battery manufacture will always provide thefloating charging voltage value for the specific type of the battery.When the solar charge maximizer is not charging the battery, the MPPTsolar charge controller will still be charging the battery to top itoff. Because the solar energy from all the solar panels is stillavailable to the MPPT solar charge controller when the solar chargemaximizer stops charging according to present invention.

It is the contractor, field technician or the system designer'sresponsibility to make sure the system will include other components,such as combiner boxes, DC circuits breakers, disconnects and systemgrounding as per local electrical standards and codes. The current limitfor each of the components and wiring shall all be lower than themaximum current limit allowed according to the local electricalstandards and the codes.

The potential application opportunity of present invention in the largescale of grid-tie systems, such as solar generator station overcommercial building and solar plant, is also enormous. The solar chargemaximizer system will sure outperform the string inverter system, sinceit is less likely to be affected by the changing solar conditions. Itwill also solve the high maintenance cost, and unreliable componentsissues that has become very common in the micro-inverter and optimizersystems in recent years. All the solar charge maximize system componentsincluding the lithium-ion batteries or battery banks can be located inthe electrical rooms or hydro vaults to ensure the reliability, andserviceable throughout the years.

DESCRIPTION OF DRAWINGS AND EMBODIMENT

FIG. 1 illustrates a typical solar array arrangement for a solar powersystem exemplary embodiment with solar charge maximizer 100. The highvoltage wire 105 from the panels connected in series 117 charge thebattery or battery bank 108 through the traditional MPPT solar chargecontroller 107. This is a common negative system with the commonnegative solar charge maximizer 100 works in conjunction with a commonnegative MPPT solar charge controller 107 to charge the same battery orbattery bank 108 in the system, and to power an off-grid inverter 109directly. The off-grid inverter 109 supplies the AC power to anautomatic transfer switch that can be set to transfer power sourcebetween the solar energy and another power source, such as grid power oranother power generator. The voltage setting on the automatic transferswitch can be set at the optimum range for the solar charge maximizer tocharge the battery 108. The solar panels 102 with same nominal voltageas the battery 108 are connected in parallel. The split wire 104 fromthe common panel 103 also has the same nominal voltage of the battery orbattery bank 108. The split wire is connected to the positive terminalof all other panels 102 connected in parallel. The split wire (PVs)charges the battery or battery bank 108 through the solar chargemaximizer 100. The large portion of the charging current is conductedthrough the mechanical contact switch (or switches) inside the solarcharge maximizer 100, so that the MPPT solar controller 107 does notneed to handle high charging current. The components overheating in MPPTsolar charge controller is minimized. And the solar energy harvestingand utilization for the whole solar array is maximized. The split wireconnection 104 with solar panels connected in the combination of seriesand parallel and the solar charge maximizer 100 are the exemplaryembodiment of the present invention.

FIG. 2 is a configuration diagram of a common negative solar chargemaximizer 100, according to the exemplary embodiment of the presentinvention. The negative terminal 101 is connected directly to thebattery or battery bank negative terminal. The negative terminal passingthrough the solar charge maximizer 100 may be connected to an electricalshunt or a Hall-Effect current sensor for charging current monitoringand display. The control module 110 has the terminals for split wirevoltage signal connection. The control module 110 has a “start” buttonand a “stop” button that are pre-set in the factory for lithium-ionphosphate battery charging. It also allows the users to change “start”and “stop” charging voltage setting values on site. The control module110 will send electrical power to the control relay 111 to close therelay contact for direct charging. The control module 110 may also beconnected to a current or temperature sensor to activate the secondrelay, or even third or fourth relay to close the switches in stages tomaximize the charge current at maximum solar radiation condition. Thefirst stage relay can be sized according to the minimum solar radiationcondition, so minimum current is needed to pull the first contactswitch. All the contact switch (or switches) shall all be opened whenthe battery voltage, as well as the split wire voltage will reach thepreset stop charging value. The control module 110 may be connected tothe display 112 to show the battery voltage, split wire voltage,charging current, charging power, and total energy has been charged inwatt hours or kilowatt hours. The control switch 114 may turn on or offthe solar charge maximizer 100. The wakeup switch 113 can be turned onto wake up a lithium-ion battery or a battery bank with BMS that hadswitched off the lithium-ion battery for over-current draw protection.The wakeup switch 113 may also be used to pre-charge an inverter priorto the battery hookup. The LED indicator may be used to indicate theswitch conditions. This exemplary embodiment shows a common negativesolar charge maximizer. The solar positive wire 105 is not connected tothe solar charge maximizer 100. The diagram shows the solar positivewiring 105 bypassing the solar charge maximizer 100, and it is to beconnected to a common negative MPPT solar charge controller.

A common positive solar charge maximizer would have very similarconstruction, except for the solar positive terminal would be connecteddirectly, but the split wire 104 from the solar array is stillcontrolled by the relay switches 111 through the control module 110. Andthe solar negative wire has to bypass the solar charge maximizer, and tobe connected to the common positive MPPT solar charge controller.

FIG. 3 is a diagram illustrating how a common negative solar chargingmaximizing system can be expanded to further increase the currentcapacity. In a single common negative MPPT solar charge controller 107and common negative solar charge maximizer 100 system, another group ofsolar panels with combination of series and parallel connection can beintegrated into the original group with panel 102, as long as theirsplit wire 104 have same nominal voltage. The same nominal voltage ofsolar positive wire 105 from panels 117 connected in series can also beconnected to the same common negative MPPT solar charge controller 107.This kind of configuration may be implemented in a house or smallbuilding with different roof orientations and/or with shading fromnearby structure or tree. The shading 115 on any one of the panels 102connected in parallel will have no impact on the energy output of allother panels in the system. The shading on one of the panels in series117 will have no impact on the energy output from other strings. Thereare also common panels 103 in such systems. The solar energy from allcommon panels 103 is still available for solar charge maximizer 100 withsplit wire 104 connected to the same port. The solar energy from allcommon panels 103 is also available for the MPPT solar charge controller107 connected to the solar positive terminal (PV+).

FIG. 4 is another possible system arrangement of an exemplary embodimentaccording to present invention. There could be another or even more ofthe common negative MPPT solar charge controllers 107 in the systemcharging the same battery or battery bank, along with the commonnegative solar charge maximizer 100. The other group of solar panels hasan extra solar panel 120. The solar photovoltaic voltage PV2+ isdifferent from the PV1+ in the other group. The MPPT solar chargecontroller in the group 120 may have a higher voltage input than thePV1+ from other group. This kind of configuration may be used for ahouse or small building with different orientation in each part of theroof. One part of the roof may receive less solar radiation in themorning, and the other part of the roof may receive less solar radiationin the afternoon. The shading 119 may reduce the solar energy outputfrom PV2+ wire, but shading 119 will not affect the performance of wholegroup with PV1+ terminal. The split wire 104 with same nominal voltagecan still be connected to the same single solar charge maximizer 100.Because the solar minimum and maximum radiation condition has verylittle impact on the optimum charging point of a group of solar panelsconnected in parallel, as illustrated in FIG. 5. Also, the every solarpanel in the solar maximizer system has a blocking diode according tothe present invention.

FIG. 5 illustrates the I-V curves of a typical 60 cells solar panelunder standard testing condition (STC 25 C) at varying solar radiationconditions. This diagram proved that the direct mechanical switchcontact charging method (on/off charging method) through the split wire,according to present invention is appropriate method in all solarradiation conditions from minimum to maximum, as long as all the panelshas the same nominal voltage, and the temperature range is near or belowthe STC conditions. This method is suitable for charging lithium-ionbased battery without gassing issues. It is also good for charging othertypes of battery, such as GEL, AGM and Lead acid batteries, as long asthe “stop” charge voltage value is set below the floating charge voltagerequired by the battery manufacturers, according to present invention.It is appropriate for the panels in parallel serving split wirecircuitry to have 72 cells for a 24V nominal voltage system when thepanels are installed in hot climate region. Through the voltage controlof an automatic transfer switch in the system, the battery voltage canalways be maintained between 25.0 v and 28.0 v_the optimum voltage rangefor direct charging. Maintaining optimum charging point method willeliminate the fluctuating current output as it would normally be seen ina MPPT solar charge controller system. In the mean time, cost for a highcurrent MPPT solar charge controller is not required. Also, theoverheating in the MPPT solar charge controller components can beprevented.

In a 12V nominal voltage system, the cell number and voltage valueillustrated here would be reduced to half. In a 48V nominal voltagesystem, the cell number and voltage value illustrated here would bedoubled.

FIG. 6 illustrates how the harvested overall solar energy may bemaximized by relocating some of the solar panels in series for a MPPTsolar charge controller system to be connected in parallel and chargingthe battery though the split wire in a solar maximizer system, accordingto the present invention. The total solar energy harvested is maximizedfor following reasons. 1. The optimum operating points are maintainedfor all the solar panels connected in parallel, as compared to a MPPTsolar charge controller system where shading on one panel can havedramatic impact on all other panels connected in series. 2. The solarenergy harvesting is steady in any given solar radiation conditions, ascompared to the charging current fluctuation that normally appears in aMPPT solar charge controller system. 3. The current flow through themechanical contact switch (or switches) may generate minimum heat in anysolar conditions, as compared to the significant heat may be generatedin a MPPT solar charge controller system, especially at maximum solarconditions. 4. As a matter of fact, majority energy of a solar array isharvested at maximum solar radiation conditions. A MPPT solar chargecontroller can waste significant amount of energy at maximum solarconditions, when the overheating of its components happens.

FIG. 7 is a diagram illustrating an exemplary embodiment of a commonpositive solar charge maximizer system according to present invention.In a common positive solar charge maximizer system, both MPPT solarcharge controller 121 and the solar charge maximizer 100 must be ofcommon positive design. In the common positive solar charge maximizersystem, the solar positive wire PV+ 105 is hard-wired to the batterypositive terminal through the solar charge maximizer 100 without anycontrol. If the solar array needs to be grounded, the solar positive andthe battery positive terminal shall be grounded. The solar negative isnot grounded in a common positive system, and the solar split wire PVsmust never be grounded. There are also panels 102 connected in parallel,and panels 117 connected in series in the common positive system. Thereis also at least one common panel 103 in the system. In a commonpositive solar charge maximizer system, both common positive MPPT solarcharge controller 212 and common positive solar charge maximizer 100 arestill charging the same battery or battery bank 108. The battery orbattery bank voltage is still maintained by the off-grid inverter and anautomatic transfer switch 109. In common positive system, the PV+terminal of the MPPT solar charge controller is not necessarilyconnected.

FIG. 8 is a diagram illustrating another exemplary embodiment accordingto present invention. Two or three more solar charge maximizers 100 withdifferent nominal voltages can be integrated into one single unit,called master solar charge maximizer (MSCM). The split wires PVs1, PVs2and PVs3 with the matching nominal voltage of the batteries (BAT1, BAT2and BAT3) are connected to the corresponding terminals in the mastersolar charge maximizer. There may be one or more MPPT solar chargecontrollers 107 in the same system serving corresponding batteries. Thebatteries 108 with different nominal voltages must not be connected tothe same MPPT solar charge controller. Different MPPT solar chargecontroller may share the same solar positive terminal PV+, but they mustall be of the same common negative design, or same common positivedesign. The exemplary embodiment in this diagram shows a common negativedesign. The negative terminals are connected to the earth ground in thissystem. Alternatively, the solar positive may be connected to the earthground, but both positive and negative battery terminals must befloating in a master solar charge maximizer system with solar positiveground connection.

FIG. 9 is a diagram illustrating another application of the exemplaryembodiment according to present invention. The common negative solarcharge maximizer system with common negative components 100 and 107 mayactually have a common positive MPPT solar charge controller 121connected to both solar positive PV+ terminal 105 and solar negative PV−terminal 101 of the solar panels 117 connected in series. However, thesolar positive MPPT solar charge controller 121 may only be used tocharge a separated battery pack, normally refers to a portable batterypack with integrated inverter inside, such as recreation power pack. Thebattery terminal in such portable pack must not be connected to thesolar energy storage battery or battery bank 108 serving the off-gridinverter 109 that has its negative battery terminal connected to theearth ground. The battery terminals of power pack 122 must be floating.

FIG. 10 is a diagram illustrating the large scale power generatingstations or solar farms application of the exemplary embodimentaccording to claim 1. Each of the solar charge maximizer system (SCMS)can have a capacity limit of about 300 amps or 400 amps, with its ownbattery or battery bank and its own three-phase grid-tie inverters. Butthe overall total capacity can be unlimited. Many solar charge maximizersystems (SCMSs) 123 can be located in the electrical room for largebuilding, and in the underground or aboveground hydro vault in case ofsolar farm. The diagram shows common negative system, but it can also bea common positive system as long as the nominal voltage of all solarcharge maximizers and the nominal voltage of all MPPT solar chargecontroller is consistent. Each of solar positive wire connecting PV+ ofthe MPPT solar charge controller may be different, such as PV1+, PV2+,PV3+ . . . etc. But the battery or battery bank shall have the samenominal voltage as all the panels' that is connected in parallel. Thenominal voltage may be 12V, 24V, 36V, 48V or 60V, as long as the batteryor battery bank, inverter, solar panels in parallel has the same nominalvoltage. The lithium-ion based solar energy storage bank in each solarcharge maximizer system maintains the optimum voltage range (25.0 and28.0 for 24V nominal voltage system) for maximum solar energyharvesting. The three phase inverters can all be set to feed the powerto the grid when voltage reach 28.0V in 24 v system, and drop off thegrid when voltage fall below 25.0V (24.0 v system). The inverters insuch system can have an optimum capacity range with high quality productto minimize the DC injection and phase shifting to the power grid. Andthe inverters will not need to operate when the battery voltage fallbelow 25.0 in a 24 v system (50.0V in 48 v system). The inverters insuch system will have extended service life with maximum efficiency,because it does not need to run at standby mode. The service life of allother components (lithium-ion battery, solar charge maximizer, MPPTsolar charge controllers etc.) will also be extended, because all thecomponents will be located in the electrical room or the hydro vaultwith proper temperature and ventilation control.

Compared to a high DC voltage (1500V or 1000 v) of MPPT string inverterswith all panels in series serving PV power plant, or other micro-gridsystems serving large commercial and industrial buildings, the solarcharge maximizer systems still have many advantages. As compared to a1500V string inverter system, the cloud moving over one panel can havesignificant impact on the power output of the whole string. But poweroutput reduction to a solar power charge maximizer system caused by thesame cloud is much less.

1. A solar array can be configured to have some solar panels connectedin parallel, and others connected in series. In a common negative MPPTsolar charge controller system (the “PV−” and BAT−” terminals areinteriorly connected inside the MPPT solar charge controller), the solarpositive wires from the panels in parallel can be connected to the splitwire(s) of a string solar panels connected in series. The split wire(s)from the string of all panels in series has the same nominal voltage asthe solar positive terminals of all panels connected in parallel. Thesplit wire(s) can be wired to a solar charge controller, namely a solarcharge maximizer, to power a DC load directly, and to charge arechargeable battery or a rechargeable battery bank with same nominalvoltage as the split wire's nominal voltage. The rechargeable battery orbattery bank maintains the optimum charging voltage for the splitwire(s) from the solar panels connected in parallel to maximize thetotal charging current for a solar array in ever-changing solarradiation conditions.
 2. In a common negative system, the split wirefrom a solar array according to claim 1, is wired to the positiveterminals of all solar panels connected in parallel, and it is named“PVs”. The solar panel or panels, that belong(s) to both parallel andseries strings, can be called “common panel” or “common panels”. Thepositive terminal(s) of common panel(s) has (have) same nominal voltageof the DC load and battery or battery bank. “PVs” is connected to thesolar charge maximizer for the controlled power supply to DC load, andthe battery or battery bank.
 3. The solar array according to claim 1,may still have its other panels connected in series, to charge the samebattery or battery bank through a MPPT (maximum power point tracking)solar charge controller, and/or, to power the same DC load directly, aslong as the MPPT solar charge controller and the solar charge maximizeris of the same common negative design, or the same common positivedesign. In a solar charging maximizer system according to claim 1, thesolar energy from the all solar panels in the same system is stillavailable for the MPPT solar charge controller to top off the battery orbattery bank, even when the solar charge maximizer stops charging thebattery or battery bank.
 4. In a solar array according to claim 1, thenumber of the panels connected in parallel does not necessarily need tomatch the number of the panels connected in series. The panels connectedin parallel can be much more than the panels connected in series tomaximize the total current capacity of a solar array, and minimize theimpact from changing solar radiation conditions due to shading and othersolar radiation variations.
 5. In a common negative system, the solarnegative terminal (PV−) of a MPPT solar charge controller according toclaim 3, is not necessarily connected, as long as the MPPT controller isa common negative solar charge controller, and the battery negativeterminal of the MPPT solar charge controller is connected to thenegative terminal of a solar storage battery or a battery bank.
 6. Thesolar panels according to claim 1, must have its aluminum (or any othermetal) frames connected to earth ground, and bonded to the house ground,along with the chassis ground of all other electrical components in thesystem, such as an inverter and an automatic transfer switch (ATS) andother MPPT solar charge controller(s).
 7. In a common negative systemaccording to claim 1, either the solar negative terminals (PV−) may beconnected to the earth, or the solar positive terminal (PV+) may beconnected to the earth. But they must never be connected to earth at thesame time.
 8. The solar array according to claim 1, must never have itssplit wire (PVs) connected to the ground regardless it is a commonpositive or common negative system. The split wire (PVs) must always beconnected to a solar charge maximizer, and controlled by the solarcharge maximizer to supply DC load directly, or charge a battery orbattery bank.
 9. A solar charge maximizer according to claim 1, has onemechanical relay contact switch, or more relays with separated contactsto close the contact(s) in stages according to the maximum currentavailable from the solar array, to allow the high current passingthrough a solar charge maximizer without components overheating in thesolar charge maximizer. A heat sink or a cooling fan shall not berequired in a solar charging maximizer.
 10. A solar charge maximizeraccording to claim 1, has (have) one or more heat sensing switch orelements or DC current sensing switches or elements built in the solarcharge maximizer to activate the mechanical relays arranged in stagesthrough a control module. And only minimum current draw is required atinitial stage when there is minimum solar radiation condition available.There shall be another heat sensing element built inside the solarcharge maximizer to disconnect all the mechanical contacts should thetemperature inside the solar charge maximizer reaches unacceptable level(such as 65 C).
 11. The solar array according to claim 1, may includeone or more solar panel strings connected in combination of series andparallel, serving the same battery or battery bank, as long as the MPPTsolar charge controller and the solar charge maximizer are of the samecommon negative or same common positive design.
 12. A solar chargemaximizer according to claim 1, has a switch built-in, to manually orautomatically wake up a lithium-ion battery or battery bank with batterymanagement system (BMS) after the BMS had shut down the battery forover-current draw or short circuit protection.
 13. The switch accordingto claim 12, may also be used to pre-charge an inverter or invertersprior to the connection of the battery or battery bank, to preventover-current draw from a battery or battery bank at the starting up ofan inverter or more inverters.
 14. A solar charge maximizer according toclaim 1, may include a screen display to show the battery voltage,charging current, power in watts and total energy charged in KWH or thelike information. It may also include LED indicators for wake-up chargeand on/off switch state indication. And the solar charge maximizer mayalso have intelligent or web-based or cloud-based control built-in forremote or computer access or mobile devices access or even control. 15.A solar charge maximizer system according to claim 1, may include one ormore solar charge maximizer(s) to charge the same battery or batterybank, and to power the same DC load, and further increase the totalcapacity of the system, as long as they are of the same common negativeor same common positive design.
 16. The solar charge maximizer accordingto claim 1, has a lithium-ion battery-charging control module builtinside to mechanically connect or disconnect the terminals between “PVs”and the battery positive terminal “BAT+” (“BAT−” in case of a commonpositive system). The “start” and “stop” voltage setting in the chargingcontrol module may be adjusted on site.
 17. The battery or battery bankaccording to claim 1, is generally refers to the lithium-ion phosphatesolar storage battery (LiFePo4) or battery bank with battery managementsystem (BMS) built in. The battery or battery bank may also be othertypes of deep cycle solar energy storage battery without BMS, as long asthe “stop” charging setting of the solar charge maximizer is set at avoltage below the float charge voltage of a battery or battery bank.Such battery or battery bank may be of GEL, Sealed or Flooded lead-acid,AGM etc. any other type of solar energy storage battery or battery bank.18. The MPPT solar charge controller according to claim 3, shall be ableto bulk charge, trickle charge, or float charge the battery or batterybank according to the type of the battery or battery bank in the system.19. The MPPT solar charge controller according to claim 3, may includeone or more MPPT solar charge controllers from different manufactures.And the different MPPT solar charge controllers may be connected to thesame or the different solar panel strings as long as the solar stringhas the same nominal voltage.
 20. The MPPT solar charge controllersaccording to claim 19, may have a different operating voltage (PV+),such as PV1+, PV2+ . . . etc. as long as they are connected to differentstrings. And the different MPPT solar charge controllers may still beconnected to charge the same the battery or battery bank, and/or powerthe same DC load.
 21. The battery or battery bank according to claim 1,shall have a total maximum charge current capacity more than the totalcurrent capacity (at the nominal voltage) of a solar array at themaximum solar radiation condition, minus the minimum current draw fromthe DC load during the day. (A 100 AH lithium-ion based battery orbattery bank may have 0.5 C or 0.2 C or others charging currentcapacity. The 0.2 C charging capacity of a 100 AH battery may allow amaximum 20 amps charging current only)
 22. Each of the solar panelaccording to claim 1, must have one or more blocking diode(s) installedin the sealed junction box, known as J-box by the solar panelmanufactures. Or an appropriate blocking diode must be supplied andinstalled for each panel by installer on site.
 23. In a solar array andthe charging system according to claim 1, the system must be completedwith combiner boxes, disconnects, fuses etc. according to the localelectrical standards or codes. And the solar array may be either afloating array, or a grounded array. In a common negative system, thesolar positive (PV+) or solar negative (PV−) may be earth-grounded andbounded to the house ground. In common positive system, the solarpositive (PV+) may be earth-grounded. The system designer may determinewhich wire(s) shall be earth-grounded according to local electricalstandards, codes and the system design. The split wire must never beearthed and the solar positive and solar negative must not beearth-grounded at the same time in any case.
 24. The solar chargermaximizer according to claim 1, is not limited to a common negative MPPTsolar charge controller system. The solar charge maximizer can bedesigned to work in common positive MPPT solar charge controller system.In a common positive system, the solar charge maximizer, solar array,battery or battery shall have all its positive terminals physicallyconnected, except for the PV+ terminal of the MPPT solar chargecontroller. The split wire (PVs) shall still be connected to the solarcharge maximizer that is designed for common positive system.
 25. Thesolar charge maximizer according to claim 1, may have a separated commonpositive MPPT solar charge controller connected to the “PV+” and “PV−”terminal, but this common positive MPPT solar charge controller must notbe used to charge the battery or battery bank in a common negativesystem. This common positive MPPT solar charge controller may only beused to charge a separated battery or portable power pack with its owninverter, such as recreation power pack. And such portable power packmust not be grounded. No wire may be connected between the portablebattery pack and the battery bank for the power supply in the solarcharge maximizer system.
 26. The solar panels (including common panel)connected in parallel according to claim 1, shall have the same nominalvoltage as the battery or battery bank in the system. The panels inparallel and the split wire for a 12V nominal battery or battery banksystem may have the cell number of 30 or 36, depends on the localweather conditions. The higher solar panel working temperature, the morecell number would be required. The panels in series do not need to havethe same cell number, as long as they have the consistent currentrating, and the voltage between “PV+” and “PV−” is within the highvoltage limit of the MPPT solar charge controller in the system.
 27. Thecell numbers according to claim 26, shall be doubled to have 60 or 72cells in a 24V nominal voltage system, depends on local weatherconditions. The higher solar panel working temperature, the more cellnumbers would be required.
 28. The cell numbers according to claim 27,shall be doubled to have 120 or 144 in a 48V nominal voltage system,depends on local weather conditions. The higher solar panel workingtemperature, the more cell numbers would be required.
 29. A solar arrayaccording to claim 1, may include one or more solar charge maximizer(s).And the nominal voltages of the solar charge maximizers are notnecessarily the same, as long as the nominal voltage of solar chargemaximizer matches the split wire nominal voltage, and the battery orbattery bank nominal voltage, as well as DC load nominal voltage of thatbattery or battery bank.
 30. A solar array and the solar chargemaximizer (SCM) according to claim 1, may be designed and built withmany split-wire connection terminals for different nominal voltagessystem, to power the different nominal voltage DC load, and to chargethe rechargeable battery or battery bank with matching nominal voltagein the common negative terminals. Such solar charge maximizer may becalled master solar charge maximizer (MSCM).
 31. A solar chargemaximizer (SCM) according to claim 1 and/or master solar chargemaximizer (MSCM) according to claim 30, may have a terminal blocklocated outside or inside the solar charge maximizer (SCM) and/or mastersolar charge maximizer (MSCM). This terminal block may include manyconnection points, but it is not connected to any of the interiorwirings inside the SCM or MSCM. When used, this terminal block must beearthed and bonded to the house (building) earth, including the chassisearth of inverter and automatic transfer switch in the system. Thesystem designer may determine to use this block for connection betweenthe solar array, battery (or battery bank) and other solar chargecontroller(s), but the designer must determine which wire(s) in thesystem to be earth-grounded, and ensure the current load is not over thedesign limit. The designer must also ensure that the system is ofcompliance with all local electrical standards and codes.
 32. A solarcharge maximizer (SCM) according to claim 1 and/or a master solar chargemaster maximizer (MSCM) according to claim 30, must have a stickerattached to the maximizer for the field technician to record followinginformation, such as “common positive” or “common negative” system, thesolar array is a “floating array” or a “grounded array”, and “which ofthe terminals are grounded”. Such information must be left with thesolar charge maximizer(s), and accessible to any future servicetechnician(s).
 33. A solar charge maximizer (SCM) according to claim 1and/or a master solar charge master maximizer (MSCM) according to claim30, when used in a hybrid off-grid system, shall generally include anautomatic transfer switch to maintain the preferred battery voltagerange.
 34. A solar charge maximizer (SCM) and the battery or batterybank according to claim 1, may also be used in a grid-tie system withgrid-tie inverter. The solar storage capacity in the battery or batterybank of a solar charge maximizer system will also ensure the steadypower output from a solar array. And the cost for a high capacitygrid-tie inverter will be saved, yet the overall kilowatt-hour (KWH)energy from a solar array is actually increased. Such grid-tie systemmay also include a hybrid grid-tie inverter with an automatic transferswitch (ATS) to maintain preferred battery voltage range.
 35. A solarcharge maximizer (SCM) and the battery or battery bank according toclaim 1, may also be implemented at large building scale or at largesolar farm with megawatts capacity level through the integration of manysolar charge maximizer systems. The amperage capacity of each solarmaximizer system may be limited to 300 amps or 400 amps level, but theoverall system capacity can be unlimited. The battery or battery bankand the grid-tie inverters serving each system may be located close tothe corresponding solar charge maximizer and the solar array. Eachgrid-tie inverter may have a capacity range of about 10 KW to 20 KW.Such inverter may generate higher voltage three phase powers and feedthree phase powers into the grid at high voltage level to reduce thewiring cost. The inverter with such capacity level is far more efficientthen many small micro inverters, or a single huge inverter. Theinverters at this capacity range can be made to ensure the better powerquality in terms of minimizing DC injection and phase shifting. In the24V nominal voltage system, the inverters can be set to kick in at 28.0V(56V for 48V system), and drop off when the battery voltage fall below25.0 volts (doubled in a 48V system). In such system, the battery orbattery bank will still ensure the solar energy harvesting is maximized.And the equipment operating cost will be minimized since inverters willconsume minimum power at standby when the battery voltage is below 25.0V(50.0V in 48V system). The batteries or battery banks and the invertersin such system can be located in the electrical rooms of the largebuildings, or in the underground hydro vaults at many locations in thesolar farm. The temperature and ventilation control will be required insuch electrical rooms or hydro vaults, because the lithium-ion basedbattery will normally stop charging when temperature fall belowfreezing, and its' service life will be reduced when the temperaturereach over 45 C.
 36. The solar charge maximizer systems (SCMSs) and thebatteries or battery banks according to claim 35, may includes smartinverters in the systems. By increasing the solar energy storage batteryor battery bank capacity in each every solar charge maximizer system,some of the inverters may be programmed or remote-controlled to harvestsolar power during the day, and generate power any time when there is ahigh demand in the grid. With web-based or cloud-based control, suchsystem can further achieve the goal for smart energy storage at gridlevel.